2.8V fixed rail with 70dB PSRR — clean power for noise-sensitive loads
The TPS71728DCKR: Its power-supply rejection ratio (PSRR) holds 70 dB at 100 Hz and stays above 45 dB through 1 MHz, which means high-frequency switching noise from a nearby buck converter or digital rail is attenuated before it reaches the analog supply pin. Dropout voltage maxes at 300 mV at the full 150 mA load, so the input rail needs at least 3.1 V to keep the output in regulation under worst-case current. The 80 µA quiescent current (100 µA max supply) keeps the regulator's own draw low enough for battery-powered or always-on sub-circuits.
SC-70-5 package and protection set
On-chip protection covers over-current, over-temperature, reverse polarity, and under-voltage lockout (UVLO). That combination means a shorted load on the output won't cascade into the upstream supply, and a reverse-battery event on the input won't damage the regulator — useful on boards that see field service or hot-plug conditions.
Temperature grade and sourcing posture
The 125°C ceiling gives margin in an enclosure that sees 85°C internal air with self-heating from the regulator itself.